Electric resistance heating element



Jan. 1, 1935. E. 1.. WIEGAND ELECTRIC RESISTANCE HEATING ELEMENT FiledJan. 8, 1932 Z Lwl'egalzd Patented Jan. 1, 1935 p s i UNITED STATESPATENT OFFICE ELECTRIC nnsrsmncn HEATING ELEMENT Edwin L. Wiegand,Pittsburgh, Pa. Application January s, 1932, Serial No. 585,493,

19 Claims. (Cl. 201-47) This invention relates to sheathed electricedges of the companion member 6 to secure the heating elements, and theprincipal object of the sheath in position surrounding the body 2.invention is the provision of sheathed electric In the element of Figure5 the companion heating elements having increased rigidity and member 6is omitted, and the lips 5 engage di- 5 resistance to warping or otherdeformation. The reetly with the one face 1, of t dy d t invention isapplicable whether the sheath Sheath 2 overlies only one face of thebody encloses entirely or only partly, and is particu- 2, and theflthelface 10 0f the dy 2 is p larly applicable to sheathed electric heatingbetween the lips 5. elements of the type disclosed in my United In eachof the Elements O ur 1 o h 4 states Patents 1,613,426, 1,614,330,1,614,331, and the sheath 8 is p v d n each of its face mm 10 1,614,938,that is, to sheathed el ctric heating eltions 3 and 6 with pr d ru aions 7, and ements comprising a resistor enclosed in a body in theelement of Figure 5 the Sheath 12 is p of electrically-insulatingheat-conducting mate- Vided With impressed fl a ons 3 Over its rialwholly or partly enclosed by a metal sheath single f i each of th men sof Fi u s 15 supporting and protecting the body and acti 1 through 4 thecorrugations 7 are straight, and 15 as a heat-transfer surface for theelement, and depressed inwardly, Shown, a d in he elein this a licationI have illustrated my invenmerit of Figure 5 t u a i ns 13 ar h ok d,tion embodied in heating elements of that type. and raisedo d y- In thedrawing accompanying this specifica- I prefer, however, that the r u tons be tion and forming a part of this application: straight, and 3 thatthe corrugations be de- 20 Figure 1 is a view in perspective, showing apressed inwardly, in order not substantially to ring element of thattype and embodying my 1m impair the contact between the surface of thevention, sheath and a cooking vessel or other article to Figure 2 is asimilar view, but showing a strip be heated, or air or other flu d flowacross element, the surface. 25

Figure 3 is a second view f, th el t, of In each element thecorrugations are at an Figure 2, showing the element the other side up,angle o e length (lithe element (in the r Figure 4 is a iew similar toFigure 3, "but unit, 50 the circumference), to strengthen and showing acurved element, and may be t k a stiffen the face of the sheath, and toallow a fragmentary view of a portion ofthe element 1701 expansion inthe direction of the length, 30 of Figure 1, showing the element theother side and in the elements of Figures 'm 4 the andcorrugations ofthe two faces 3 and 6 are in- Figure 5 is a view in perspective,illustrating dined relatively fipp y, to Secure even the application ofthe invention to an element greater rigiditywherein the sheath onlypartially encloses. the fillegoing it will be apparent, that 35 Each ofthe heating elements herein shown the elements herein wn are of greaterrigcomprises a resistor La body 2 of cementitious idiliy and1135151331109 t0 deformation, a d aeelectrically-insulatingheat-conducting material wrdihgly, that my invention does accomplishembedding the resistor 1, and a sheath wholly a l a t s principal pu p Hw v it is to 40 or partly enclosing the body 2, and in h i be understoodthat the invention is not limited 4Q stance the resistor 1 is in theform of a ribbon, t0 the particuifll heating elemehtS yp o disposedsinuously in the body 2. heating elements herein shown, or to theparticuni'th l t of Figures 1 through 4 t lar forms herein shown, butmay be otherwise sheath 8 is two-part, entirely surrounding theembodied, has uses and a es, body 2, and consists of a channel member sand and eeeerdnisly e dlseleeure herein is o b 45 a cooperatingcompanion member 6, and in each regarded as llltl-stlatlve on y, and theinvention of these elements the companion member 6 is is not limitedtheretomerely a wide flat metal strip overlying one face av thusdescribed my inv ntion what I 10 of the body 2, and the channel member 9is a claim r151 metal member having a wide flat portion 3 over-- 1. Anelectrical resistance heating element 50 lying the other face 10 of thebody 2, having edge comprising a resistor of flat formation arrangedportions 4 rising from the edgesof the flat perto present heating areasof considerable expanse, tion 3 and overlying the sides 11 of the body2, a metal sheath adjacent said resistor and spaced and havingalso lips5 inturned from the free therefrom, substantially co-extensive with saidedges of the edge portions 4 and overlying the heating areas andcontinuously subject to the 55 influence of said resistor, and a compactmass of refractory, electrically non-conducting material filling thespace between said resistor and sheath, said sheath having reinforcingcorrugations embossed therein and projecting into said non-conductingmaterial.

2. An electrical resistance heating element, comprising: a resistor; asheath at least partly embracing said resistor; and electricallynonconductive material insulating said sheath from said resistor; saidsheath having an operative surface provided with spaced corrugationsdepressed inwardly thereof, providing said opera tive surface with flatsurfaces of substantial area between said corrugations, whereby the hatsurfaces are adapted to contact the article to be heated.

3. An electrical resistance heating element, comprising: a resistor; asheath at least partly embracing said resistor; and electricallynonconductive material insulating said sheath from said resistor; saidsheath having a plurality of operative surfaces provided with spacedcorrugations depressed inwardly thereof, providing said operativesurfaces with flat surfaces of substantial area between saidcorrugations, where by the flat surfaces of any one of said operativesurfaces are adapted to contact the article to be heated.

4.1 m electrical resistance heating element, comprising: a resistor; asheath at least partly embracing said resistor; and electricallynonconductive material insulating said sheath from said resistor; saidsheath having operative surface provided with spaced corrugationsdepressed therein, projecting into said non-conductive material,providing said operative surface with fiat surfaces of substantial areabetween said corrugations, whereby the flat surfaces are adapted tocontact the article to be heated.

5. An electrical resistance heating element, comprising: a resistor; asheath at least partly embracing said resistor; and electricallynonconductive material insulating said sheath from said resistor; saidsheath having a pair of oppositely disposed operative surfaces providedwith biased spaced corrugations depressed inwardly thereof, and thecorrugations of the opposite operative surfaces inclined in opposeddiagonal directions. said cor'ugations being arran ed to provide op tivcsurfaces with fiat surfaces of substantial area therebetween, wherebythe flat surfaces of one of said operative surfaces adapted to contactthe article to be heated.

6.1m electrical r ce heating element, comprising: a resistor; a sheathat least ,artially emhra ng resistor; said being provided vii. i. a.plurality of con .gations, disposed at a substantial angle to the lengththereof effective both to strengthen said sheath transversely and totake up longitudinal expansion.

7. An electrical resistance heating element, comprising: a resistor; anda sheath at least partially embracing said resistor; said sheath beingprovided with a plurality of corrugations, disposedat a substantialangle to the length thereof substantially less than a right angle andeffective both to strengthen said sheath both transversely andlongitudinally and also to take up both transverse and longitudinalexpansion.

8. A relatively flat electrical resistance heating element, comprising:a resistor; and a sheath embracing said resistor on at least one of thetwo fiat sides of the element; said sheath being provided in its flatface with a plurality of corrugations, disposed at a substantial angleto the length thereof effective both to strengthen said facetransversely and to take up longitudinal expansion.

9. A relatively flat electrical resistance heating element, comprising:a resistor; and a sheath embracing said resistor on at least one of thetwo flat sides of the element; said sheath being provided in its fiatface with a plurality of corrugations, disposed at a substantial angleto the length thereof substantially less than a right angle andeffective both to strengthen said face both transversely andlongitudinally and also to take up both transverse and longitudinalexpansion.

10. A relatively flat electrical resistance heating element, comprising:a resistor, and a sheath embracing said resistor on both of the flatsides of the element; said sheath being provided in each of its flatfaces with a. plurality of corrugations, disposed at a substantial angleto the length thereof substantially less than a right angle and inclinedoppositely to the corrugations in the other face and effective both tostrengthen said faces both transversely and longitudinally and also totake up both transverse and longitudinal expansion.

11. An electrical resistance heating element, comprising: a resistor;and a sheath at least partially embracing said resistor; said sheathbeing provided with inwardly depressed spaced corrugations, leavingtherebetween contact surfaces of considerable area, adapted to beengaged by an article to be heated.

12. A relatively flat electrical resistance heating element, comprising:a resistor; and a sheath embracing said resistor on at least one of thetwo fiat sides of the element; said sheath being provided with inwardlydepressed spaced corrugations, leaving therebetween flat contactsurfaces of considerable area, adapted to be engaged by an article to beheated.

13. An electrical resistance heating element, comprising: a resistor; abody of electrically-insulating heat conducting material embedding saidresistor; and a metal sheath at least partially enclosing said body;said sheath being provided with a plurality of corrugations, dis posedat a substantial angle to the length there of effective both tostrengthen said sheath transversely and to take up longitudinalexpansion.

14. An. electrical resistance heath clement, comprisin a resistor; abody el ct' callyinsulatin heat-conducting material dding tor; and asheath at least partially i said body; said sheath bein provided with aplurality of corrugations, disposed at a substantial angle to the lengththereof substantially less than a right angle and effective both tostrengthen said sheath both transversely and longitudinally and also totake up both transverse and longitudinal expansion.

15. A relatively fiat electrical resistance heating element, comprising:a resistor; a body of electrically-insulating heat-conducting materialembedding said resistor; and a sheath enclosing said body on at leastone of the two flat sides of the element; said sheath being provided inits flat face with a plurality of corrugations, disposed at asubstantial angle to the length thereof eflective both to strengthensaid face transversely and. to take up longitudinal expansion.

16. A relatively flat electrical resistance heating element, comprising:a resistor; a body of electrically-insulating heat-conducting materialembedding said resistor; and a sheath enclosing said body on at leastone of the two fiat sides of the element; said sheath being provided inits flat face with a plurality of corrugations, disposed at asubstantial angle to the length thereof substantially less than a rightangle and effective both to strengthen said face .both transversely andlongitudinally and also to take up both transverse and longitudinalexpansion.

17. A relatively fiat electrical resistance heating element, comprising:a resistor; a body of electrically-insulating heat-conducting materialembedding said resistor; and a sheath enclosing said resistor on both ofthe flat sides of the element; said sheath being provided in each of itsfiat faces with a plurality of corrugations, disposed at a substantialangle to the length thereof substantially less than a right angle andinclined oppositely to the corrugations in the other face and effectiveboth to strengthen said faces both transversely and longitudinally andalso to take up both transverse and longitudinal expansion.

18. An electrical resistance heating element, comprising: a resistor; abody of electrically-insulating heat-conducting material embedding saidresistor; and a sheath at least partially enclosing said body; saidsheath being provided with inwardly depressed spaced corrugationsextending into said body, said corrugations leaving therebetween contactsurfaces of considerable area, adapted to be engaged by an article to beheated.

19. A relatively flat electrical resistance heating element, comprising:a resistor; a body of electrically-insulating heat-conducting materialembedding said resistor; and a sheath enclosing said body on at leastone of the two flat sides of the element; said sheath being providedwith inwardly depressed spaced corrugations extending into said body,said corrugations leaving therebetween fiat contact surfaces ofconsiderable area, adapted to be engaged by an article to be heated.

EDWIN L. WIEGAND.

